[Interview file] Climate change makes a strong and lasting typhoon

The reason we pay great attention to climate change and meteorological issues is that meteorological phenomena happening here and there have a great influence on our lives.

Heavy rains, heavy snow, heat waves and cold waves are also scary, but the most fearful is typhoons, which have a fatal effect in a short period of time.

In 2003, the strongest typhoon among the typhoons that visited Korea, Typhoon Maemi passed through Yeongnam, killing 131 people.

Until now, it has been an interest to us how climate change will affect these typhoons.

Although there have been many studies, various results have been produced, ranging from an analysis that the typhoon will become stronger to an analysis that it will become weaker.

As science advances, more precise analysis is becoming possible, but unfortunately, the recently released results gave a hand to the analysis that the typhoon will become stronger.

domestic research team analyzed how warming affects typhoons by controlling the concentration of carbon dioxide that affects climate change.

As a result, after 50 years, the overall frequency of typhoons decreases, but the'very strong' typhoons, whose central wind speed exceeds 50m/s, were 1.5 times slower.

Winds exceeding 50m/s are powerful winds that can derail trains and upset running cars.

In 2003, a cicada instantaneously recorded a wind of 60 m/s and knocked down a steel crane.

The Meteorological Administration also created a typhoon rating called'Super Power' this year as the intensity of typhoons intensified, and at around 50 m/s, it reaches a'very strong' rating just below the'Super Power', the highest level.

The typhoons that landed in Korea this year were not the century of order, but the central wind speed of Typhoon No. 10 High Ship once developed into a'super powerful' typhoon reaching 55m/s in the southern sea of ​​Okinawa, raising tensions.

At that time, 1 person disappeared and 5 people were injured due to the impact of the typhoon High Sun, and 124 people were displaced.

There were also 724 cases of damage to facilities nationwide.

typhoons are caused by the interaction of the ocean and the atmosphere.

The vertical difference in wind between the upper and lower layers of the atmosphere and water vapor supplied from the warm sea are the key factors in creating a typhoon.

The research team predicted that if the earth warms due to warming, the temperature difference between the upper and lower layers of the atmosphere will decrease, and the upward current in the tropics will weaken.

Most of the air molecules in the atmosphere are concentrated in the lower atmosphere, and when water vapor increases due to warming, this water vapor is also concentrated in the lower atmosphere.

Due to the specific heat of the concentrated water vapor, the temperature in the lower layer increases slowly, and the temperature in the upper atmosphere with relatively little water vapor increases rapidly.

As the ascending air current in the tropics is weakened, cyclones are not formed in this area, and the frequency of typhoons, which are tropical cyclones, decreases.

However, once a typhoon occurs due to the right conditions of occurrence, it is possible to receive abundant water vapor from the hotter sea than now, and it can develop stronger than it is now.

The research team confirmed that the same results were obtained from typhoons* in the North Pacific Ocean* and hurricanes* in the North Atlantic Ocean.

This study is evaluated for analyzing the ocean and atmosphere more closely than the model used to predict typhoons.

This is because the Earth was divided more closely than the existing models** to better reflect the weather phenomena, temperature, and topographical differences by region that have been overlooked.

*If the central wind speed exceeds 17m per second among the low pressures that occur in the tropics, it is called a tropical cyclone. The ones that occur in the Pacific Ocean are called typhoons, the Atlantic Ocean is called a hurricane, and the Indian Ocean is called a cyclone.

** Existing typhoon prediction model Global grid, about 100 km of atmosphere and ocean l This model grid, 25 km of atmosphere, 10 km of ocean.

No matter how strong a typhoon, it is enough if it disappears in the far sea where we do not live.

The reason typhoons become a problem is because it affects the inland where we are.

Fortunately, when the typhoon landed inland, it lost energy and disappeared within a day or two.

This is because water vapor is no longer supplied and friction occurs with the surface.

However, research has shown that global warming slows the disappearance of typhoons.

The research team has conducted research on hurricanes that occur in the North Atlantic Ocean. In fact, when a hurricane landed inland in the late 1960s, 75% of the energy was lost, and now it is only 50%.

That is, you can work longer with more energy in the interior.

Until now, it has not been known which factors play a major role in the extinction of typhoons, but this study showed that water vapor has a profound effect on the extinction of typhoons.

Of course, because it is a study on hurricanes that affect North America, it is difficult to compare it with typhoons that affect Korea in one to one.

However, it seems like the case in Korea that water vapor plays a more role in the disappearance of typhoons than friction, and that typhoons containing more water vapor than before due to global warming will extinguish later.

Unlike earthquakes or unpredictable natural disasters, typhoons can be predicted at least 2-3 days in advance.

However, even if you know in advance and prepare, it always leaves a lot of scars.

While preparing for typhoons near the coast, which is vulnerable to the landing of typhoons, it is said that the inland cannot be assured as in the past.

Although the events caused by climate change may not appear as close results in a year or two, it is true that things that were thought only to be the work of our generation are coming faster and faster.

Already we are living in a changed climate.

It's not the future anymore.

Considering the seasonal characteristics of typhoons, it is a distant story now in winter, but it seems necessary to prepare for the long term, not 2-3 days after the forecast of typhoons that will change due to climate change.

Lin Li*Pinaki Chakraborty, "Slower decay of landfalling hurricanes in a

warming world", nature (2020) 587, 230–234, doi.org/10.1038/s41586-020-2867-7

Jung-Eun Chu* , Sun-Seon Lee, Axel Timmermann, Christian Wengel, Malte F. Stuecker, Ryohei Yamaguchi, "Reduced tropical cyclone densities and ocean effects due to anthropogenic greenhouse warming", Science Advances (2020) Vol.

6, no.

51,

doi: 10.1126/sciadv.abd5109